Because life is unpredictable, and so are we. When things go wrong, take a deep breath, and do one of the following:
When the situation gets too hot, just leave it all behind. Literally, leave the ship. Find a new, quieter place to be.
No need to admit the truth when you can claim it's just a miscommunication or an oversight. People will believe you; it's science!
Denial is a powerful tool. Just pretend the situation never occurred, and it might just work. It's like magic, but with less magic.
Ask a question about the question, and then ask another question about the answer. This is called "redirecting the question," and it's very effective.